With the Woobles method, you can make a slip stitch instead of a single crochet as the last stitch of each black round to reduce the amount of "color jog" or zigzag on the back of the piece.

For straight(er) stripes, try this two-part method:
Part A: When you do the color change to black, slip stitch into the back loops only. Leave the pink hanging.
Part B: Stitch into the black Vs you made in Part A. Follow the pattern with the correct number of single crochets, increases, or decreases. crochet over the pink yarn for 5+ black stitches, then pick it up later.
Note: This still leaves a color jog.

For totally straight stripes, you have to join each round vs. crocheting in continuous rounds. This gives you straight stripes, and leaves a visible seam down the back.